feat(daemon): record evaluate subprocess token_usage in database (#716)

- Add runtime_name and model fields to belt agent --json output
- Add parse_ipc_token_usage() method on EvaluateResult to extract
  TokenUsage, runtime_name, and model from subprocess IPC JSON
- Record parsed token usage to DB after run_evaluate subprocess path
- Add IpcTokenUsage struct and try_record_ipc_token_usage() helper

Closes #677

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: kys0213

crates/belt-cli/src/agent.rs

@@ -535,6 +535,8 @@ pub async fn run_agent(
                         "cache_read_tokens": u.cache_read_tokens,
                         "cache_write_tokens": u.cache_write_tokens,
                     })),
+                    "runtime_name": action_result.runtime_name,
+                    "model": action_result.model,
                 });
                 println!("{}", serde_json::to_string_pretty(&output)?);
             } else {

crates/belt-daemon/src/daemon.rs

@@ -1596,7 +1596,20 @@ impl Daemon {
                     Err(e) => Err(e),
                 }
             } else {
-                self.evaluator.run_evaluate(&self.belt_home).await
+                let result = self.evaluator.run_evaluate(&self.belt_home).await;
+
+                // Parse and record token usage from subprocess IPC JSON output.
+                if let Ok(ref eval_result) = result
+                    && let Some(ref ipc_usage) = eval_result.parse_ipc_token_usage()
+                {
+                    for work_id in &completed {
+                        if let Some(item) = self.queue.iter().find(|i| i.work_id == *work_id) {
+                            self.try_record_ipc_token_usage(item, ipc_usage);
+                        }
+                    }
+                }
+
+                result
             }
         };
 
@@ -2237,6 +2250,41 @@ impl Daemon {
         }
     }
 
+    /// Record token usage parsed from evaluate subprocess IPC JSON output.
+    ///
+    /// When the evaluate subprocess runs via `belt agent --json`, the stdout
+    /// JSON may contain `token_usage`, `runtime_name`, and `model` fields.
+    /// This method extracts those and records them to the DB.
+    fn try_record_ipc_token_usage(
+        &self,
+        item: &QueueItem,
+        ipc_usage: &crate::evaluator::IpcTokenUsage,
+    ) {
+        if let Some(ref db) = self.db {
+            let model = ipc_usage.model.as_deref().unwrap_or("unknown");
+            if let Err(e) = db.record_token_usage(
+                &item.work_id,
+                &self.config.name,
+                &ipc_usage.runtime_name,
+                model,
+                &ipc_usage.token_usage,
+                ipc_usage.duration_ms,
+            ) {
+                tracing::warn!(
+                    "failed to record evaluate IPC token usage for {}: {e}",
+                    item.work_id
+                );
+            } else {
+                tracing::debug!(
+                    "recorded evaluate IPC token usage for {}: input={}, output={}",
+                    item.work_id,
+                    ipc_usage.token_usage.input_tokens,
+                    ipc_usage.token_usage.output_tokens
+                );
+            }
+        }
+    }
+
     fn record_history(&mut self, item: &QueueItem, status: &str, error: Option<&str>) {
         let attempt = self
             .history
@@ -4474,6 +4522,84 @@ sources:
         assert_eq!(rows[0].model, "unknown");
     }
 
+    // ---------------------------------------------------------------
+    // IPC token usage recording tests
+    // ---------------------------------------------------------------
+
+    #[test]
+    fn try_record_ipc_token_usage_saves_to_db() {
+        use belt_core::runtime::TokenUsage;
+        use belt_infra::db::Database;
+
+        let tmp = TempDir::new().unwrap();
+        let source = MockDataSource::new("github");
+        let db = Database::open_in_memory().unwrap();
+        let daemon = setup_daemon(&tmp, source, vec![]).with_db(db);
+
+        let item = test_item("github:org/repo#10", "analyze");
+        let ipc_usage = crate::evaluator::IpcTokenUsage {
+            token_usage: TokenUsage {
+                input_tokens: 800,
+                output_tokens: 400,
+                cache_read_tokens: Some(30),
+                cache_write_tokens: None,
+            },
+            runtime_name: "claude".to_string(),
+            model: Some("opus-4".to_string()),
+            duration_ms: Some(2500),
+        };
+
+        daemon.try_record_ipc_token_usage(&item, &ipc_usage);
+
+        let rows = daemon
+            .db
+            .as_ref()
+            .unwrap()
+            .get_token_usage_by_work_id("github:org/repo#10:analyze")
+            .unwrap();
+        assert_eq!(rows.len(), 1);
+        assert_eq!(rows[0].input_tokens, 800);
+        assert_eq!(rows[0].output_tokens, 400);
+        assert_eq!(rows[0].model, "opus-4");
+        assert_eq!(rows[0].runtime, "claude");
+    }
+
+    #[test]
+    fn try_record_ipc_token_usage_uses_unknown_model_when_absent() {
+        use belt_core::runtime::TokenUsage;
+        use belt_infra::db::Database;
+
+        let tmp = TempDir::new().unwrap();
+        let source = MockDataSource::new("github");
+        let db = Database::open_in_memory().unwrap();
+        let daemon = setup_daemon(&tmp, source, vec![]).with_db(db);
+
+        let item = test_item("github:org/repo#11", "analyze");
+        let ipc_usage = crate::evaluator::IpcTokenUsage {
+            token_usage: TokenUsage {
+                input_tokens: 100,
+                output_tokens: 50,
+                cache_read_tokens: None,
+                cache_write_tokens: None,
+            },
+            runtime_name: "gemini".to_string(),
+            model: None,
+            duration_ms: None,
+        };
+
+        daemon.try_record_ipc_token_usage(&item, &ipc_usage);
+
+        let rows = daemon
+            .db
+            .as_ref()
+            .unwrap()
+            .get_token_usage_by_work_id("github:org/repo#11:analyze")
+            .unwrap();
+        assert_eq!(rows.len(), 1);
+        assert_eq!(rows[0].model, "unknown");
+        assert_eq!(rows[0].runtime, "gemini");
+    }
+
     // ---------------------------------------------------------------
     // advance_ready_to_running: HashMap per-workspace concurrency (additional)
     // ---------------------------------------------------------------

crates/belt-daemon/src/evaluator.rs

@@ -7,6 +7,7 @@ use anyhow::Result;
 use belt_core::action::Action;
 use belt_core::phase::QueuePhase;
 use belt_core::queue::QueueItem;
+use belt_core::runtime::TokenUsage;
 
 use crate::executor::{ActionEnv, ActionExecutor, ActionResult};
 
@@ -301,10 +302,63 @@ pub struct EvaluateResult {
     pub ipc_result: Option<serde_json::Value>,
 }
 
+/// Token usage and runtime metadata parsed from subprocess IPC JSON output.
+#[derive(Debug, Clone)]
+pub struct IpcTokenUsage {
+    pub token_usage: TokenUsage,
+    pub runtime_name: String,
+    pub model: Option<String>,
+    pub duration_ms: Option<u64>,
+}
+
 impl EvaluateResult {
     pub fn success(&self) -> bool {
         self.exit_code == 0
     }
+
+    /// Parse token usage from the subprocess IPC JSON output.
+    ///
+    /// When the evaluate subprocess is invoked with `--json`, the stdout
+    /// contains a JSON object with optional `token_usage`, `runtime_name`,
+    /// and `model` fields. This method extracts those fields into an
+    /// [`IpcTokenUsage`] for DB recording.
+    ///
+    /// Returns `None` if `ipc_result` is absent, or if `token_usage` or
+    /// `runtime_name` is missing from the JSON.
+    pub fn parse_ipc_token_usage(&self) -> Option<IpcTokenUsage> {
+        let json = self.ipc_result.as_ref()?;
+        let tu = json.get("token_usage")?;
+        if tu.is_null() {
+            return None;
+        }
+        let runtime_name = json.get("runtime_name")?.as_str()?;
+        if runtime_name.is_empty() {
+            return None;
+        }
+
+        let input_tokens = tu.get("input_tokens")?.as_u64()?;
+        let output_tokens = tu.get("output_tokens")?.as_u64()?;
+        let cache_read_tokens = tu.get("cache_read_tokens").and_then(|v| v.as_u64());
+        let cache_write_tokens = tu.get("cache_write_tokens").and_then(|v| v.as_u64());
+
+        let model = json
+            .get("model")
+            .and_then(|v| v.as_str())
+            .map(|s| s.to_string());
+        let duration_ms = json.get("duration_ms").and_then(|v| v.as_u64());
+
+        Some(IpcTokenUsage {
+            token_usage: TokenUsage {
+                input_tokens,
+                output_tokens,
+                cache_read_tokens,
+                cache_write_tokens,
+            },
+            runtime_name: runtime_name.to_string(),
+            model,
+            duration_ms,
+        })
+    }
 }
 
 impl From<ActionResult> for EvaluateResult {
@@ -1760,4 +1814,165 @@ exit {exit_code}
         let child_output = result.unwrap().unwrap();
         assert_eq!(child_output.status.code().unwrap(), 0);
     }
+
+    // --- Tests for parse_ipc_token_usage ---
+
+    #[test]
+    fn parse_ipc_token_usage_extracts_full_fields() {
+        let json = serde_json::json!({
+            "exit_code": 0,
+            "token_usage": {
+                "input_tokens": 1000,
+                "output_tokens": 500,
+                "cache_read_tokens": 50,
+                "cache_write_tokens": 25,
+            },
+            "runtime_name": "claude",
+            "model": "opus-4",
+            "duration_ms": 3200,
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+
+        let ipc_usage = result
+            .parse_ipc_token_usage()
+            .expect("should parse token usage from IPC JSON");
+        assert_eq!(ipc_usage.token_usage.input_tokens, 1000);
+        assert_eq!(ipc_usage.token_usage.output_tokens, 500);
+        assert_eq!(ipc_usage.token_usage.cache_read_tokens, Some(50));
+        assert_eq!(ipc_usage.token_usage.cache_write_tokens, Some(25));
+        assert_eq!(ipc_usage.runtime_name, "claude");
+        assert_eq!(ipc_usage.model.as_deref(), Some("opus-4"));
+        assert_eq!(ipc_usage.duration_ms, Some(3200));
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_returns_none_without_ipc_result() {
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: None,
+        };
+        assert!(result.parse_ipc_token_usage().is_none());
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_returns_none_when_token_usage_null() {
+        let json = serde_json::json!({
+            "exit_code": 0,
+            "token_usage": null,
+            "runtime_name": "claude",
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+        assert!(result.parse_ipc_token_usage().is_none());
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_returns_none_when_runtime_name_missing() {
+        let json = serde_json::json!({
+            "exit_code": 0,
+            "token_usage": {
+                "input_tokens": 100,
+                "output_tokens": 50,
+            },
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+        assert!(result.parse_ipc_token_usage().is_none());
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_returns_none_when_runtime_name_empty() {
+        let json = serde_json::json!({
+            "exit_code": 0,
+            "token_usage": {
+                "input_tokens": 100,
+                "output_tokens": 50,
+            },
+            "runtime_name": "",
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+        assert!(result.parse_ipc_token_usage().is_none());
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_handles_optional_cache_tokens() {
+        let json = serde_json::json!({
+            "exit_code": 0,
+            "token_usage": {
+                "input_tokens": 200,
+                "output_tokens": 100,
+                "cache_read_tokens": null,
+                "cache_write_tokens": null,
+            },
+            "runtime_name": "gemini",
+            "duration_ms": 1500,
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+
+        let ipc_usage = result
+            .parse_ipc_token_usage()
+            .expect("should parse even with null cache tokens");
+        assert_eq!(ipc_usage.token_usage.input_tokens, 200);
+        assert_eq!(ipc_usage.token_usage.output_tokens, 100);
+        assert!(ipc_usage.token_usage.cache_read_tokens.is_none());
+        assert!(ipc_usage.token_usage.cache_write_tokens.is_none());
+        assert_eq!(ipc_usage.runtime_name, "gemini");
+        assert!(ipc_usage.model.is_none());
+    }
+
+    #[test]
+    fn parse_ipc_token_usage_without_model_and_duration() {
+        let json = serde_json::json!({
+            "token_usage": {
+                "input_tokens": 50,
+                "output_tokens": 25,
+            },
+            "runtime_name": "codex",
+        });
+        let result = EvaluateResult {
+            exit_code: 0,
+            stdout: String::new(),
+            stderr: String::new(),
+            action_result: None,
+            ipc_result: Some(json),
+        };
+
+        let ipc_usage = result
+            .parse_ipc_token_usage()
+            .expect("should parse without model and duration");
+        assert_eq!(ipc_usage.runtime_name, "codex");
+        assert!(ipc_usage.model.is_none());
+        assert!(ipc_usage.duration_ms.is_none());
+    }
 }